Attenuation effects of iron on dissemination of antibiotic resistance genes in anaerobic bioreactor: Evolution of quorum sensing, quorum quenching and dynamics of community composition

• Published in: Journal of hazardous materials 2021-08, Vol.416, p.126136-126136, Article 126136
• Main Authors: Xu, Yi, Yang, Shihong, You, Guoxiang, Hou, Jun
• Format: Article
• Language: English
• Subjects: Antibiotic resistance genes; Microbial community composition; Mobile genetic elements; Quorum sensing; Zero valent iron
• ISSN: 0304-3894; 1873-3336
• DOI: 10.1016/j.jhazmat.2021.126136

Zero valent iron (ZVI) coupled with bioreactors is arising as a promising technology for antibiotic resistance genes (ARGs) mitigation, whereas the succession and behaviors of microbes caused by ZVI in relieving ARGs propagation remain unclear. Herein, the effects of ZVI on microbial quorum sensing (QS), quorum quenching (QQ) system and community dynamics were examined in anaerobic bioreactor fed with oxytetracycline (tet), to illustrate the roles of evolutive microbial communication and community composition in ARGs attenuation. With the addition of 5 g/L ZVI, the total absolute abundance of tet ARGs was retarded by approximate 95% and 72% in sludge and effluent after 25 days operation. The abundance of mobile genetic elements and the heredity of antibiotic resistant bacteria revealed the declined horizontal and vertical transfer of ARGs, which directly led to the reduced ARGs propagation. Potential mechanisms are that the positive effects of ZVI on QQ activity via the functional bacteria enrichment inhibited QS system and thus ARGs transfer. Partial least--squares path modeling further demonstrated that ARGs abundance was strongly limited by the dynamics of bacterial composition and thereby less frequent microbial communication. These results provide new insights into the mechanisms of antibiotic resistome remission in anaerobic bioreactor modified by ZVI. [Display omitted] •Zero valent iron could mitigate ARGs propagation in anaerobic bioreactor.•Horizontal transfer of ARGs and proliferation of resistant strains were suppressed.•The weakened bacterial communication led to decreased ARGs transfer.•The reduced potential host bacteria contributed to relieving ARGs dissemination.